The present invention relates to a method for cost-orientated monitoring and/or display of the operating condition of a replaceable or regenerable conditioning device, flowed through by a fluid, in a whole installation, in particular of a filter, wherein by means of at least one sensor at least one value from which the state of wear of the conditioning device can be deduced is measured continuously or at intervals.
Installations of this type have been known for a long time. For example, in [1] "H. G. Heitmann: Praxis der Kraftwerk-Chemie, Vulcan-Verlag, Essen (1986)" several installations of the known type are described: It deals, for example, with cartridge filters (see [1], page 166 ff.) with filter elements configured as filter cartridges for the mechanical cleansing of liquids which, for example, can be wrapped with metal cladding of different mesh sizes or with plastics threads. So-called pre-coated filters are also used (see [1], page 148 ff.) in which the filter element is covered with an auxiliary filter layer. After reaching a certain loss of pressure, filters of this type are regenerated by flushing in the opposite direction with clean liquid or with a regenerating medium.
Installations of the known type are also described in [2] "Grundlagen fur Industrielle Wasserbehandlung, Drew Chemical Corporation, Boonton, N.J. U.S.A. (1980)": These are containers filled, for example, with gravel, sand or anthracite (see [2], page 24 ff.), which are flowed through by the liquid to be cleansed and after reaching a certain decrease in pressure are back-washed with liquid or compressed air.
Filters with cartridge-type filter elements with very fine pores are also used in compressed air installations, which, after reaching a certain decrease in pressure, have to be replaced with replacement filter elements.
In motor vehicle technology also, filters have the task of protecting the engines from solid contaminants. In [3] "P. Gerigk et al: Kraftfahrzeugtechnik. Westermann-Verlag, Braunschweig (1994)" on page 162 ff. filters are described with very different filter elements for the filtering of air, fuel and oil. The filter elements of these filters are also replaced with new ones when worn out.
Further conditioning devices of the known type are described in [1] on page 149 ff.: Magnetic filters, in particular electromagnetic filters, cleanse liquids of ferro-magnetic pollutants. In this case metallic spheres, for example, form the filter element, and are contained in a filter container surrounded by an electric coil and flowed through by the liquid to be cleansed. The exhaustion of the filter can be recognized by measurement of the pressure differential.
Other conditioning devices of the known type are, for example, desalination plants in which salty water flows through filter elements equipped with filter membranes and is separated according to the principle of reverse osmosis (see [1], page 229 ff.) into lowsalt permeate and salt-rich concentrate. With these installations the state of wear of the filter elements is checked by pressure measurement, and when a certain pressure is reached regeneration is carried out. Ion exchangers are also used as conditioning devices for desalination (see [1], page 135 ff.).
A conditioning device for fluids, to which the invention relates, generally means all devices and installations which condition fluids, that is to say, for example, cleanse them of mechanical or chemical contaminants or remove dissolved contents or alter the temperature or the state of aggregation of the fluid. To that extent, the examples set out above do not fully describe the wide range of conditioning devices to which the invention relates. Air filters are used in air conditioning installations, drinking water is deodorized with activated charcoal filters. Common to all these installations described and all further known installations to which the invention relates is that they are conditioning devices for fluids, and these conditioning devices are subject to wear and have to be regenerated or replaced after complete technical exhaustion. The state of wear is determined in that at least one value from which the state of wear can be deduced is measured continuously or at intervals.
For renewal of the conditioning devices, they must in many cases be taken partially or completely out of service. Depending on the particular device, the conditioning device is renewed by regenerating or replacing the fouled filter. For this, from several parallel conditioning devices, one device is isolated from the fluid flow by closing shut-off means, so that the operation of the whole installation does not have to be interrupted.
Devices are also known in which some areas of the conditioning device, in particular several component filter elements arranged in a single housing can be isolated from the fluid flow one after another on the inlet side or the inlet and outlet sides, and then a renewal can be carried out without the fluid flow through the housing having to be interrupted. Such a device is, for example, described in German patent DE 41 07 432.
Conditioning devices are also known in which although the renewal, which includes regeneration or replacement, is associated with expenditures and costs, it can, however, be carried out without any interruption to service at all.
As a whole, for the renewal of the conditioning devices, there is expenditure on regenerating medium and/or energy for cleaning and/or expenditure on personnel and/or costs for down-time and/or costs for the replacement elements and for the disposal of the worn-out elements. Normally, therefore, renewal is determined by a state of wear of the conditioning device which is close to complete technical exhaustion, at which, so to speak, a technological limit is reached.
Naturally, there are also diverse plans for optimizing the operation of the installation taking into account the costs of the conditioning device. This is done, typically, by determining certain dependencies of the parameters specific to the installation when installations are set up. This has the disadvantage that once-optimized conditioning strategies do not react to different conditioning needs occurring, changed costs of conditioning media and/or varying energy costs. In the case of production facilities, for example, the product output is taken with respect to the critical working condition, wherein production times and down-time periods are weighted with different cost factors.
The disadvantage of this manner of proceeding is in that the effects of the state of wear of the conditioning device upon the operating costs of the whole installation are insufficiently taken account of. With increasing wear the technological characteristics of the conditioning device change, as a rule, such that there are higher operating costs for the whole installation. For example, the loss of pressure significantly increases in a filter flowed through by a constant amount of fluid flow, for cleansing pollutants from fluids, with a constant total amount of fluid flow, which causes increased pump output to maintain the amount of fluid flow and thereby higher energy consumption. The capacity of conditioning devices is mainly explained by their suppliers in terms of long "useful life" wherein, for example, for filter cartridges in compressed air installations the limit value of loss of pressure indicating the necessity of a replacement is stated as being very high. This is, for example, approximately 500 mbar for a filter cartridge which in clean condition with a nominal through-flow has a pressure loss of 35 mbar. In this example, the operator waits to replace the filter cartridge with a new one at least until the limit value for the pressure loss described has been reached. In many cases the operator will further delay replacement still further in order to have the lowest possible expenditure for the provision of new filter cartridges and for replacement without, in very many cases, considering at all the increase in operating costs of the whole installation. It is also disadvantageous that in many cases the conditioning devices have periodically varying operating conditions, for example, having a periodically differing amount of fluid flow. For example, the pressure loss of a filter cartridge changes significantly when there is the same state of wear, which very much limits the capacity for meaningful normal indication of wear by means of the pressure loss.
This prior art is not only disadvantageous for the individual operator, as the increased operating costs of the whole installation can be significantly higher than the expense of renewal of the conditioning device. The prior art described is also disadvantageous economically and with respect to the environment, as costs and environmental damage through avoidable energy consumption rise constantly. In this sense it is also significant that in most cases the technical and business management expertise necessary for evaluating the operating costs of the whole installation cannot be taken for granted for the individual operator.
Methods and devices are also known which relate the indication of pressure differential to a certain value of the amount of fluid flow, and thereby eliminate the contingencies of the measurement of pressure differential from it (DE 42 24 721 A1), or even make possible an display of the remaining life-time to be expected until technological exhaustion (EP 0 527 136 A1). All this, however, does not overcome the disadvantages of the prior art described above.
Also the DE 31 16 610 does not overcome the disadvantages known from prior art. This document discloses a method for controlling a filter wherein the controlling is made due to characterizing criteria. To this reason, an efficiency of a filtration operation is defined which depends on a maximum filter performance and on so-called self-costs of filter operating during a term of operating cycle of the filter. One operating cycle encloses on one hand the operating time but on the other hand also the replacement time for a filter. The source force of one filtration operation, which is defined as P in the above mentioned document, is adjusted in dependance to the maximum efficiency of the filtration operation and to a pressure lost over the filter. So-called auxiliary work and interruptions of filter operation are adjusted in dependance to the filtration time, the amount of filtration operating cycle, respectively. An optimized controlling of the filter shell be achieved when first the efficiency criteria of a filtration operation is calculated, then the determining of an extreme value of the efficiency criteria is followed depending to the time, the source force and the number of filtration cycle. Correspondent to the gained values, a stop of the filter for taking through the auxiliary work, a predicting of a value as a start value for the source force of the filtration operation and the interruption of the filtration for the replacement of the filter are also done. For rating the times among one the other in the formula of the efficiency criteria, the period of filtration work, the period of auxiliary work and the period of complete renewal of the filter have cost-factored time measures. These time measures weight every time wherein these weights in case of realization the filtration operating in respect to a maximum performance have the value 1.